ChatCerebras#

class langchain_cerebras.chat_models.ChatCerebras[source]#

Bases: BaseChatOpenAI

ChatCerebras chat model.

Setup:

Install langchain-cerebras and set environment variable CEREBRAS_API_KEY.

pip install -U langchain-cerebras
export CEREBRAS_API_KEY="your-api-key"

Key init args — completion params:

model: str: Name of model to use.
temperature: float: Sampling temperature.
max_tokens: Optional[int]: Max number of tokens to generate.

Key init args — client params:

timeout: Union[float, Tuple[float, float], Any, None]: Timeout for requests.
max_retries: int: Max number of retries.
api_key: Optional[str]: Cerebras API key. If not passed in will be read from env var CEREBRAS_API_KEY.

Instantiate:

from langchain_cerebras import ChatCerebras

llm = ChatCerebras(
    model="llama-3.3-70b",
    temperature=0,
    max_tokens=None,
    timeout=None,
    max_retries=2,
    # api_key="...",
    # other params...
)

Invoke:

messages = [
    (
        "system",
        "You are a helpful translator. Translate the user sentence to French.",
    ),
    ("human", "I love programming."),
]
llm.invoke(messages)

AIMessage(
    content='The translation of "I love programming" to French is:\n\n"J\'adore programmer."',
    response_metadata={
        'token_usage': {'completion_tokens': 20, 'prompt_tokens': 32, 'total_tokens': 52},
        'model_name': 'llama-3.3-70b',
        'system_fingerprint': 'fp_679dff74c0',
        'finish_reason': 'stop',
    },
    id='run-377c2887-30ef-417e-b0f5-83efc8844f12-0',
    usage_metadata={'input_tokens': 32, 'output_tokens': 20, 'total_tokens': 52})

Stream:

for chunk in llm.stream(messages):
    print(chunk)

content='' id='run-3f9dc84e-208f-48da-b15d-e552b6759c24'
content='The' id='run-3f9dc84e-208f-48da-b15d-e552b6759c24'
content=' translation' id='run-3f9dc84e-208f-48da-b15d-e552b6759c24'
content=' of' id='run-3f9dc84e-208f-48da-b15d-e552b6759c24'
content=' "' id='run-3f9dc84e-208f-48da-b15d-e552b6759c24'
content='I' id='run-3f9dc84e-208f-48da-b15d-e552b6759c24'
content=' love' id='run-3f9dc84e-208f-48da-b15d-e552b6759c24'
content=' programming' id='run-3f9dc84e-208f-48da-b15d-e552b6759c24'
content='"' id='run-3f9dc84e-208f-48da-b15d-e552b6759c24'
content=' to' id='run-3f9dc84e-208f-48da-b15d-e552b6759c24'
content=' French' id='run-3f9dc84e-208f-48da-b15d-e552b6759c24'
content=' is' id='run-3f9dc84e-208f-48da-b15d-e552b6759c24'
content=':\n\n' id='run-3f9dc84e-208f-48da-b15d-e552b6759c24'
content='"' id='run-3f9dc84e-208f-48da-b15d-e552b6759c24'
content='J' id='run-3f9dc84e-208f-48da-b15d-e552b6759c24'
content="'" id='run-3f9dc84e-208f-48da-b15d-e552b6759c24'
content='ad' id='run-3f9dc84e-208f-48da-b15d-e552b6759c24'
content='ore' id='run-3f9dc84e-208f-48da-b15d-e552b6759c24'
content=' programmer' id='run-3f9dc84e-208f-48da-b15d-e552b6759c24'
content='."' id='run-3f9dc84e-208f-48da-b15d-e552b6759c24'
content='' response_metadata={'finish_reason': 'stop', 'model_name': 'llama-3.3-70b', 'system_fingerprint': 'fp_679dff74c0'} id='run-3f9dc84e-208f-48da-b15d-e552b6759c24'

Async:

await llm.ainvoke(messages)

# stream:
# async for chunk in (await llm.astream(messages))

# batch:
# await llm.abatch([messages])

AIMessage(
    content='The translation of "I love programming" to French is:\n\n"J\'adore programmer."',
    response_metadata={
        'token_usage': {'completion_tokens': 20, 'prompt_tokens': 32, 'total_tokens': 52},
        'model_name': 'llama-3.3-70b',
        'system_fingerprint': 'fp_679dff74c0',
        'finish_reason': 'stop',
    },
    id='run-377c2887-30ef-417e-b0f5-83efc8844f12-0',
    usage_metadata={'input_tokens': 32, 'output_tokens': 20, 'total_tokens': 52})

Tool calling:

from langchain_core.pydantic_v1 import BaseModel, Field

llm = ChatCerebras(model="llama-3.3-70b")

class GetWeather(BaseModel):
    '''Get the current weather in a given location'''

    location: str = Field(
        ..., description="The city and state, e.g. San Francisco, CA"
    )

class GetPopulation(BaseModel):
    '''Get the current population in a given location'''

    location: str = Field(
        ..., description="The city and state, e.g. San Francisco, CA"
    )

llm_with_tools = llm.bind_tools([GetWeather, GetPopulation])
ai_msg = llm_with_tools.invoke(
    "Which city is bigger: LA or NY?"
)
ai_msg.tool_calls

[
    {
        'name': 'GetPopulation',
        'args': {'location': 'NY'},
        'id': 'call_m5tstyn2004pre9bfuxvom8x',
        'type': 'tool_call'
    },
    {
        'name': 'GetPopulation',
        'args': {'location': 'LA'},
        'id': 'call_0vjgq455gq1av5sp9eb1pw6a',
        'type': 'tool_call'
    }
]

Structured output:

from typing import Optional

from langchain_core.pydantic_v1 import BaseModel, Field


class Joke(BaseModel):
    '''Joke to tell user.'''

    setup: str = Field(description="The setup of the joke")
    punchline: str = Field(description="The punchline to the joke")
    rating: Optional[int] = Field(description="How funny the joke is, from 1 to 10")


structured_llm = llm.with_structured_output(Joke)
structured_llm.invoke("Tell me a joke about cats")

Joke(
    setup='Why was the cat sitting on the computer?',
    punchline='To keep an eye on the mouse!',
    rating=7
)

JSON mode:

json_llm = llm.bind(response_format={"type": "json_object"})
ai_msg = json_llm.invoke(
    "Return a JSON object with key 'random_ints' and a value of 10 random ints in [0-99]"
)
ai_msg.content

' {\\n"random_ints": [\\n13,\\n54,\\n78,\\n45,\\n67,\\n90,\\n11,\\n29,\\n84,\\n33\\n]\\n}'

Token usage:

ai_msg = llm.invoke(messages)
ai_msg.usage_metadata

{'input_tokens': 37, 'output_tokens': 6, 'total_tokens': 43}

Response metadata

ai_msg = llm.invoke(messages)
ai_msg.response_metadata

{
    'token_usage': {
        'completion_tokens': 4,
        'prompt_tokens': 19,
        'total_tokens': 23
        },
    'model_name': 'mistralai/Mixtral-8x7B-Instruct-v0.1',
    'system_fingerprint': None,
    'finish_reason': 'eos',
    'logprobs': None
}

Note

ChatCerebras implements the standard Runnable Interface. 🏃

The Runnable Interface has additional methods that are available on runnables, such as with_types, with_retry, assign, bind, get_graph, and more.

param cache: BaseCache | bool | None = None#

Whether to cache the response.

If true, will use the global cache.
If false, will not use a cache
If None, will use the global cache if it’s set, otherwise no cache.
If instance of BaseCache, will use the provided cache.

Caching is not currently supported for streaming methods of models.

param callback_manager: BaseCallbackManager | None = None#: Deprecated since version 0.1.7: Use callbacks() instead. It will be removed in None==1.0.

Callback manager to add to the run trace.

param callbacks: Callbacks = None#: Callbacks to add to the run trace.

param cerebras_api_base: str [Optional] (alias 'base_url')#

param cerebras_api_key: SecretStr | None [Optional] (alias 'api_key')#: Automatically inferred from env are CEREBRAS_API_KEY if not provided.

param cerebras_proxy: str [Optional]#

param custom_get_token_ids: Callable[[str], list[int]] | None = None#: Optional encoder to use for counting tokens.

param default_headers: Mapping[str, str] | None = None#

param default_query: Mapping[str, object] | None = None#

param disable_streaming: bool | Literal['tool_calling'] = False#

Whether to disable streaming for this model.

If streaming is bypassed, then stream()/astream() will defer to invoke()/ainvoke().

If True, will always bypass streaming case.
If “tool_calling”, will bypass streaming case only when the model is called with a tools keyword argument.
If False (default), will always use streaming case if available.

param disabled_params: Dict[str, Any] | None = None#

Parameters of the OpenAI client or chat.completions endpoint that should be disabled for the given model.

Should be specified as {"param": None | ['val1', 'val2']} where the key is the parameter and the value is either None, meaning that parameter should never be used, or it’s a list of disabled values for the parameter.

For example, older models may not support the ‘parallel_tool_calls’ parameter at all, in which case disabled_params={"parallel_tool_calls: None} can ben passed in.

If a parameter is disabled then it will not be used by default in any methods, e.g. in with_structured_output(). However this does not prevent a user from directly passed in the parameter during invocation.

param extra_body: Mapping[str, Any] | None = None#: Optional additional JSON properties to include in the request parameters when making requests to OpenAI compatible APIs, such as vLLM.

param frequency_penalty: float | None = None#: Penalizes repeated tokens according to frequency.

param http_async_client: Any | None = None#: Optional httpx.AsyncClient. Only used for async invocations. Must specify http_client as well if you’d like a custom client for sync invocations.

param http_client: Any | None = None#: Optional httpx.Client. Only used for sync invocations. Must specify http_async_client as well if you’d like a custom client for async invocations.

param include_response_headers: bool = False#: Whether to include response headers in the output message response_metadata.

param logit_bias: Dict[int, int] | None = None#: Modify the likelihood of specified tokens appearing in the completion.

param logprobs: bool | None = None#: Whether to return logprobs.

param max_retries: int = 2#: Maximum number of retries to make when generating.

param max_tokens: int | None = None#: Maximum number of tokens to generate.

param metadata: dict[str, Any] | None = None#: Metadata to add to the run trace.

param model_kwargs: Dict[str, Any] [Optional]#: Holds any model parameters valid for create call not explicitly specified.

param model_name: str [Required] (alias 'model')#: Model name to use.

param n: int = 1#: Number of chat completions to generate for each prompt.

param openai_api_base: str | None = None (alias 'base_url')#: Base URL path for API requests, leave blank if not using a proxy or service emulator.

param openai_api_key: SecretStr | None [Optional] (alias 'api_key')#

param openai_organization: str | None = None (alias 'organization')#: Automatically inferred from env var OPENAI_ORG_ID if not provided.

param openai_proxy: str | None [Optional]#

param presence_penalty: float | None = None#: Penalizes repeated tokens.

param rate_limiter: BaseRateLimiter | None = None#: An optional rate limiter to use for limiting the number of requests.

param reasoning_effort: str | None = None#

Constrains effort on reasoning for reasoning models.

o1 models only.

Currently supported values are low, medium, and high. Reducing reasoning effort can result in faster responses and fewer tokens used on reasoning in a response.

Added in version 0.2.14.

param request_timeout: float | Tuple[float, float] | Any | None = None (alias 'timeout')#: Timeout for requests to OpenAI completion API. Can be float, httpx.Timeout or None.

param seed: int | None = None#: Seed for generation

param stop: List[str] | str | None = None (alias 'stop_sequences')#: Default stop sequences.

param streaming: bool = False#: Whether to stream the results or not.

param tags: list[str] | None = None#: Tags to add to the run trace.

param temperature: float = 0.7#: What sampling temperature to use.

param tiktoken_model_name: str | None = None#: The model name to pass to tiktoken when using this class. Tiktoken is used to count the number of tokens in documents to constrain them to be under a certain limit. By default, when set to None, this will be the same as the embedding model name. However, there are some cases where you may want to use this Embedding class with a model name not supported by tiktoken. This can include when using Azure embeddings or when using one of the many model providers that expose an OpenAI-like API but with different models. In those cases, in order to avoid erroring when tiktoken is called, you can specify a model name to use here.

param top_logprobs: int | None = None#: Number of most likely tokens to return at each token position, each with an associated log probability. logprobs must be set to true if this parameter is used.

param top_p: float | None = None#: Total probability mass of tokens to consider at each step.

param verbose: bool [Optional]#: Whether to print out response text.

__call__(messages: list[BaseMessage], stop: list[str] | None = None, callbacks: list[BaseCallbackHandler] | BaseCallbackManager | None = None, **kwargs: Any) → BaseMessage#

Deprecated since version langchain-core==0.1.7: Use invoke() instead. It will not be removed until langchain-core==1.0.

Parameters:

messages (list[BaseMessage])
stop (list[str] | None)
callbacks (list[BaseCallbackHandler] | BaseCallbackManager | None)
kwargs (Any)

Return type:

BaseMessage

async abatch(inputs: list[Input], config: RunnableConfig | list[RunnableConfig] | None = None, *, return_exceptions: bool = False, **kwargs: Any | None) → list[Output]#

Default implementation runs ainvoke in parallel using asyncio.gather.

The default implementation of batch works well for IO bound runnables.

Subclasses should override this method if they can batch more efficiently; e.g., if the underlying Runnable uses an API which supports a batch mode.

Parameters:

inputs (list[Input]) – A list of inputs to the Runnable.
config (RunnableConfig | list[RunnableConfig] | None) – A config to use when invoking the Runnable. The config supports standard keys like ‘tags’, ‘metadata’ for tracing purposes, ‘max_concurrency’ for controlling how much work to do in parallel, and other keys. Please refer to the RunnableConfig for more details. Defaults to None.
return_exceptions (bool) – Whether to return exceptions instead of raising them. Defaults to False.
kwargs (Any | None) – Additional keyword arguments to pass to the Runnable.

Returns:

A list of outputs from the Runnable.

Return type:

list[Output]

async abatch_as_completed(inputs: Sequence[Input], config: RunnableConfig | Sequence[RunnableConfig] | None = None, *, return_exceptions: bool = False, **kwargs: Any | None) → AsyncIterator[tuple[int, Output | Exception]]#

Run ainvoke in parallel on a list of inputs, yielding results as they complete.

Parameters:

inputs (Sequence[Input]) – A list of inputs to the Runnable.
config (RunnableConfig | Sequence[RunnableConfig] | None) – A config to use when invoking the Runnable. The config supports standard keys like ‘tags’, ‘metadata’ for tracing purposes, ‘max_concurrency’ for controlling how much work to do in parallel, and other keys. Please refer to the RunnableConfig for more details. Defaults to None. Defaults to None.
return_exceptions (bool) – Whether to return exceptions instead of raising them. Defaults to False.
kwargs (Any | None) – Additional keyword arguments to pass to the Runnable.

Yields:

A tuple of the index of the input and the output from the Runnable.

Return type:

AsyncIterator[tuple[int, Output | Exception]]

async ainvoke(input: LanguageModelInput, config: RunnableConfig | None = None, *, stop: list[str] | None = None, **kwargs: Any) → BaseMessage#

Default implementation of ainvoke, calls invoke from a thread.

The default implementation allows usage of async code even if the Runnable did not implement a native async version of invoke.

Subclasses should override this method if they can run asynchronously.

Parameters:

input (LanguageModelInput)
config (Optional[RunnableConfig])
stop (Optional[list[str]])
kwargs (Any)

Return type:

BaseMessage

async astream(input: LanguageModelInput, config: RunnableConfig | None = None, *, stop: list[str] | None = None, **kwargs: Any) → AsyncIterator[BaseMessageChunk]#

Default implementation of astream, which calls ainvoke. Subclasses should override this method if they support streaming output.

Parameters:

input (LanguageModelInput) – The input to the Runnable.
config (Optional[RunnableConfig]) – The config to use for the Runnable. Defaults to None.
kwargs (Any) – Additional keyword arguments to pass to the Runnable.
stop (Optional[list[str]])

Yields:

The output of the Runnable.

Return type:

AsyncIterator[BaseMessageChunk]

async astream_events(input: Any, config: RunnableConfig | None = None, *, version: Literal['v1', 'v2'], include_names: Sequence[str] | None = None, include_types: Sequence[str] | None = None, include_tags: Sequence[str] | None = None, exclude_names: Sequence[str] | None = None, exclude_types: Sequence[str] | None = None, exclude_tags: Sequence[str] | None = None, **kwargs: Any) → AsyncIterator[StandardStreamEvent | CustomStreamEvent]#

Generate a stream of events.

Use to create an iterator over StreamEvents that provide real-time information about the progress of the Runnable, including StreamEvents from intermediate results.

A StreamEvent is a dictionary with the following schema:

event: str - Event names are of the
format: on_[runnable_type]_(start|stream|end).
name: str - The name of the Runnable that generated the event.
run_id: str - randomly generated ID associated with the given execution of
the Runnable that emitted the event. A child Runnable that gets invoked as part of the execution of a parent Runnable is assigned its own unique ID.
parent_ids: List[str] - The IDs of the parent runnables that
generated the event. The root Runnable will have an empty list. The order of the parent IDs is from the root to the immediate parent. Only available for v2 version of the API. The v1 version of the API will return an empty list.
tags: Optional[List[str]] - The tags of the Runnable that generated
the event.
metadata: Optional[Dict[str, Any]] - The metadata of the Runnable
that generated the event.
data: Dict[str, Any]

Below is a table that illustrates some events that might be emitted by various chains. Metadata fields have been omitted from the table for brevity. Chain definitions have been included after the table.

ATTENTION This reference table is for the V2 version of the schema.

event	name	chunk	input	output
on_chat_model_start	[model name]		{“messages”: [[SystemMessage, HumanMessage]]}
on_chat_model_stream	[model name]	AIMessageChunk(content=”hello”)
on_chat_model_end	[model name]		{“messages”: [[SystemMessage, HumanMessage]]}	AIMessageChunk(content=”hello world”)
on_llm_start	[model name]		{‘input’: ‘hello’}
on_llm_stream	[model name]	‘Hello’
on_llm_end	[model name]		‘Hello human!’
on_chain_start	format_docs
on_chain_stream	format_docs	“hello world!, goodbye world!”
on_chain_end	format_docs		[Document(…)]	“hello world!, goodbye world!”
on_tool_start	some_tool		{“x”: 1, “y”: “2”}
on_tool_end	some_tool			{“x”: 1, “y”: “2”}
on_retriever_start	[retriever name]		{“query”: “hello”}
on_retriever_end	[retriever name]		{“query”: “hello”}	[Document(…), ..]
on_prompt_start	[template_name]		{“question”: “hello”}
on_prompt_end	[template_name]		{“question”: “hello”}	ChatPromptValue(messages: [SystemMessage, …])

In addition to the standard events, users can also dispatch custom events (see example below).

Custom events will be only be surfaced with in the v2 version of the API!

A custom event has following format:

Attribute	Type	Description
name	str	A user defined name for the event.
data	Any	The data associated with the event. This can be anything, though we suggest making it JSON serializable.

Here are declarations associated with the standard events shown above:

format_docs:

def format_docs(docs: List[Document]) -> str:
    '''Format the docs.'''
    return ", ".join([doc.page_content for doc in docs])

format_docs = RunnableLambda(format_docs)

some_tool:

@tool
def some_tool(x: int, y: str) -> dict:
    '''Some_tool.'''
    return {"x": x, "y": y}

prompt:

template = ChatPromptTemplate.from_messages(
    [("system", "You are Cat Agent 007"), ("human", "{question}")]
).with_config({"run_name": "my_template", "tags": ["my_template"]})

Example:

from langchain_core.runnables import RunnableLambda

async def reverse(s: str) -> str:
    return s[::-1]

chain = RunnableLambda(func=reverse)

events = [
    event async for event in chain.astream_events("hello", version="v2")
]

# will produce the following events (run_id, and parent_ids
# has been omitted for brevity):
[
    {
        "data": {"input": "hello"},
        "event": "on_chain_start",
        "metadata": {},
        "name": "reverse",
        "tags": [],
    },
    {
        "data": {"chunk": "olleh"},
        "event": "on_chain_stream",
        "metadata": {},
        "name": "reverse",
        "tags": [],
    },
    {
        "data": {"output": "olleh"},
        "event": "on_chain_end",
        "metadata": {},
        "name": "reverse",
        "tags": [],
    },
]

Example: Dispatch Custom Event

from langchain_core.callbacks.manager import (
    adispatch_custom_event,
)
from langchain_core.runnables import RunnableLambda, RunnableConfig
import asyncio


async def slow_thing(some_input: str, config: RunnableConfig) -> str:
    """Do something that takes a long time."""
    await asyncio.sleep(1) # Placeholder for some slow operation
    await adispatch_custom_event(
        "progress_event",
        {"message": "Finished step 1 of 3"},
        config=config # Must be included for python < 3.10
    )
    await asyncio.sleep(1) # Placeholder for some slow operation
    await adispatch_custom_event(
        "progress_event",
        {"message": "Finished step 2 of 3"},
        config=config # Must be included for python < 3.10
    )
    await asyncio.sleep(1) # Placeholder for some slow operation
    return "Done"

slow_thing = RunnableLambda(slow_thing)

async for event in slow_thing.astream_events("some_input", version="v2"):
    print(event)

Parameters:

input (Any) – The input to the Runnable.
config (RunnableConfig | None) – The config to use for the Runnable.
version (Literal['v1', 'v2']) – The version of the schema to use either v2 or v1. Users should use v2. v1 is for backwards compatibility and will be deprecated in 0.4.0. No default will be assigned until the API is stabilized. custom events will only be surfaced in v2.
include_names (Sequence[str] | None) – Only include events from runnables with matching names.
include_types (Sequence[str] | None) – Only include events from runnables with matching types.
include_tags (Sequence[str] | None) – Only include events from runnables with matching tags.
exclude_names (Sequence[str] | None) – Exclude events from runnables with matching names.
exclude_types (Sequence[str] | None) – Exclude events from runnables with matching types.
exclude_tags (Sequence[str] | None) – Exclude events from runnables with matching tags.
kwargs (Any) – Additional keyword arguments to pass to the Runnable. These will be passed to astream_log as this implementation of astream_events is built on top of astream_log.

Yields:

An async stream of StreamEvents.

Raises:

NotImplementedError – If the version is not v1 or v2.

Return type:

AsyncIterator[StandardStreamEvent | CustomStreamEvent]

batch(inputs: list[Input], config: RunnableConfig | list[RunnableConfig] | None = None, *, return_exceptions: bool = False, **kwargs: Any | None) → list[Output]#

Default implementation runs invoke in parallel using a thread pool executor.

The default implementation of batch works well for IO bound runnables.

Subclasses should override this method if they can batch more efficiently; e.g., if the underlying Runnable uses an API which supports a batch mode.

Parameters:

inputs (list[Input])
config (RunnableConfig | list[RunnableConfig] | None)
return_exceptions (bool)
kwargs (Any | None)

Return type:

list[Output]

batch_as_completed(inputs: Sequence[Input], config: RunnableConfig | Sequence[RunnableConfig] | None = None, *, return_exceptions: bool = False, **kwargs: Any | None) → Iterator[tuple[int, Output | Exception]]#

Run invoke in parallel on a list of inputs, yielding results as they complete.

Parameters:

inputs (Sequence[Input])
config (RunnableConfig | Sequence[RunnableConfig] | None)
return_exceptions (bool)
kwargs (Any | None)

Return type:

Iterator[tuple[int, Output | Exception]]

bind(**kwargs: Any) → Runnable[Input, Output]#

Bind arguments to a Runnable, returning a new Runnable.

Useful when a Runnable in a chain requires an argument that is not in the output of the previous Runnable or included in the user input.

Parameters:: kwargs (Any) – The arguments to bind to the Runnable.
Returns:: A new Runnable with the arguments bound.
Return type:: Runnable[Input, Output]

Example:

from langchain_community.chat_models import ChatOllama
from langchain_core.output_parsers import StrOutputParser

llm = ChatOllama(model='llama2')

# Without bind.
chain = (
    llm
    | StrOutputParser()
)

chain.invoke("Repeat quoted words exactly: 'One two three four five.'")
# Output is 'One two three four five.'

# With bind.
chain = (
    llm.bind(stop=["three"])
    | StrOutputParser()
)

chain.invoke("Repeat quoted words exactly: 'One two three four five.'")
# Output is 'One two'

Deprecated since version langchain-openai==0.2.1: Use bind_tools() instead. It will not be removed until langchain-openai==1.0.0.

Bind functions (and other objects) to this chat model.

Assumes model is compatible with OpenAI function-calling API.

NOTE: Using bind_tools is recommended instead, as the functions and: function_call request parameters are officially marked as deprecated by OpenAI.

Parameters:

functions (Sequence[Dict[str, Any] | Type[BaseModel] | Callable | BaseTool]) – A list of function definitions to bind to this chat model. Can be a dictionary, pydantic model, or callable. Pydantic models and callables will be automatically converted to their schema dictionary representation.
function_call (_FunctionCall | str | Literal['auto', 'none'] | None) – Which function to require the model to call. Must be the name of the single provided function or “auto” to automatically determine which function to call (if any).
**kwargs (Any) – Any additional parameters to pass to the Runnable constructor.

Return type:

Bind tool-like objects to this chat model.

Assumes model is compatible with OpenAI tool-calling API.

Parameters:

tools (Sequence[Dict[str, Any] | Type | Callable | BaseTool]) – A list of tool definitions to bind to this chat model. Supports any tool definition handled by langchain_core.utils.function_calling.convert_to_openai_tool().
tool_choice (dict | str | Literal['auto', 'none', 'required', 'any'] | bool | None) –
Which tool to require the model to call. Options are:
- str of the form "<<tool_name>>": calls <<tool_name>> tool.
- "auto": automatically selects a tool (including no tool).
- "none": does not call a tool.
- "any" or "required" or True: force at least one tool to be called.
- dict of the form {"type": "function", "function": {"name": <<tool_name>>}}: calls <<tool_name>> tool.
- False or None: no effect, default OpenAI behavior.
strict (bool | None) – If True, model output is guaranteed to exactly match the JSON Schema provided in the tool definition. If True, the input schema will be validated according to https://platform.openai.com/docs/guides/structured-outputs/supported-schemas. If False, input schema will not be validated and model output will not be validated. If None, strict argument will not be passed to the model.
kwargs (Any) – Any additional parameters are passed directly to bind().

Return type:

Changed in version 0.1.21: Support for strict argument added.

configurable_alternatives(which: ConfigurableField, *, default_key: str = 'default', prefix_keys: bool = False, **kwargs: Runnable[Input, Output] | Callable[[], Runnable[Input, Output]]) → RunnableSerializable#

Configure alternatives for Runnables that can be set at runtime.

Parameters:

which (ConfigurableField) – The ConfigurableField instance that will be used to select the alternative.
default_key (str) – The default key to use if no alternative is selected. Defaults to “default”.
prefix_keys (bool) – Whether to prefix the keys with the ConfigurableField id. Defaults to False.
**kwargs (Runnable[Input, Output] | Callable[[], Runnable[Input, Output]]) – A dictionary of keys to Runnable instances or callables that return Runnable instances.

Returns:

A new Runnable with the alternatives configured.

Return type:

RunnableSerializable

from langchain_anthropic import ChatAnthropic
from langchain_core.runnables.utils import ConfigurableField
from langchain_openai import ChatOpenAI

model = ChatAnthropic(
    model_name="claude-3-sonnet-20240229"
).configurable_alternatives(
    ConfigurableField(id="llm"),
    default_key="anthropic",
    openai=ChatOpenAI()
)

# uses the default model ChatAnthropic
print(model.invoke("which organization created you?").content)

# uses ChatOpenAI
print(
    model.with_config(
        configurable={"llm": "openai"}
    ).invoke("which organization created you?").content
)

configurable_fields(**kwargs: ConfigurableField | ConfigurableFieldSingleOption | ConfigurableFieldMultiOption) → RunnableSerializable#

Configure particular Runnable fields at runtime.

Parameters:: **kwargs (ConfigurableField | ConfigurableFieldSingleOption | ConfigurableFieldMultiOption) – A dictionary of ConfigurableField instances to configure.
Returns:: A new Runnable with the fields configured.
Return type:: RunnableSerializable

from langchain_core.runnables import ConfigurableField
from langchain_openai import ChatOpenAI

model = ChatOpenAI(max_tokens=20).configurable_fields(
    max_tokens=ConfigurableField(
        id="output_token_number",
        name="Max tokens in the output",
        description="The maximum number of tokens in the output",
    )
)

# max_tokens = 20
print(
    "max_tokens_20: ",
    model.invoke("tell me something about chess").content
)

# max_tokens = 200
print("max_tokens_200: ", model.with_config(
    configurable={"output_token_number": 200}
    ).invoke("tell me something about chess").content
)

get_num_tokens(text: str) → int#

Get the number of tokens present in the text.

Useful for checking if an input fits in a model’s context window.

Parameters:: text (str) – The string input to tokenize.
Returns:: The integer number of tokens in the text.
Return type:: int

get_num_tokens_from_messages(messages: List[BaseMessage], tools: Sequence[Dict[str, Any] | Type | Callable | BaseTool] | None = None) → int#

Calculate num tokens for gpt-3.5-turbo and gpt-4 with tiktoken package.

Requirements: You must have the pillow installed if you want to count image tokens if you are specifying the image as a base64 string, and you must have both pillow and httpx installed if you are specifying the image as a URL. If these aren’t installed image inputs will be ignored in token counting.

OpenAI reference: openai/openai-cookbook main/examples/How_to_format_inputs_to_ChatGPT_models.ipynb

Parameters:

messages (List[BaseMessage]) – The message inputs to tokenize.
tools (Sequence[Dict[str, Any] | Type | Callable | BaseTool] | None) – If provided, sequence of dict, BaseModel, function, or BaseTools to be converted to tool schemas.

Return type:

int

get_token_ids(text: str) → List[int]#

Get the tokens present in the text with tiktoken package.

Parameters:: text (str)
Return type:: List[int]

invoke(input: LanguageModelInput, config: RunnableConfig | None = None, *, stop: list[str] | None = None, **kwargs: Any) → BaseMessage#

Transform a single input into an output. Override to implement.

Parameters:

input (LanguageModelInput) – The input to the Runnable.
config (Optional[RunnableConfig]) – A config to use when invoking the Runnable. The config supports standard keys like ‘tags’, ‘metadata’ for tracing purposes, ‘max_concurrency’ for controlling how much work to do in parallel, and other keys. Please refer to the RunnableConfig for more details.
stop (Optional[list[str]])
kwargs (Any)

Returns:

The output of the Runnable.

Return type:

BaseMessage

stream(input: LanguageModelInput, config: RunnableConfig | None = None, *, stop: list[str] | None = None, **kwargs: Any) → Iterator[BaseMessageChunk]#

Default implementation of stream, which calls invoke. Subclasses should override this method if they support streaming output.

Parameters:

input (LanguageModelInput) – The input to the Runnable.
config (Optional[RunnableConfig]) – The config to use for the Runnable. Defaults to None.
kwargs (Any) – Additional keyword arguments to pass to the Runnable.
stop (Optional[list[str]])

Yields:

The output of the Runnable.

Return type:

Iterator[BaseMessageChunk]

with_alisteners(*, on_start: AsyncListener | None = None, on_end: AsyncListener | None = None, on_error: AsyncListener | None = None) → Runnable[Input, Output]#

Bind asynchronous lifecycle listeners to a Runnable, returning a new Runnable.

on_start: Asynchronously called before the Runnable starts running. on_end: Asynchronously called after the Runnable finishes running. on_error: Asynchronously called if the Runnable throws an error.

The Run object contains information about the run, including its id, type, input, output, error, start_time, end_time, and any tags or metadata added to the run.

Parameters:

on_start (Optional[AsyncListener]) – Asynchronously called before the Runnable starts running. Defaults to None.
on_end (Optional[AsyncListener]) – Asynchronously called after the Runnable finishes running. Defaults to None.
on_error (Optional[AsyncListener]) – Asynchronously called if the Runnable throws an error. Defaults to None.

Returns:

A new Runnable with the listeners bound.

Return type:

Runnable[Input, Output]

Example:

from langchain_core.runnables import RunnableLambda
import time

async def test_runnable(time_to_sleep : int):
    print(f"Runnable[{time_to_sleep}s]: starts at {format_t(time.time())}")
    await asyncio.sleep(time_to_sleep)
    print(f"Runnable[{time_to_sleep}s]: ends at {format_t(time.time())}")

async def fn_start(run_obj : Runnable):
    print(f"on start callback starts at {format_t(time.time())}
    await asyncio.sleep(3)
    print(f"on start callback ends at {format_t(time.time())}")

async def fn_end(run_obj : Runnable):
    print(f"on end callback starts at {format_t(time.time())}
    await asyncio.sleep(2)
    print(f"on end callback ends at {format_t(time.time())}")

runnable = RunnableLambda(test_runnable).with_alisteners(
    on_start=fn_start,
    on_end=fn_end
)
async def concurrent_runs():
    await asyncio.gather(runnable.ainvoke(2), runnable.ainvoke(3))

asyncio.run(concurrent_runs())
Result:
on start callback starts at 2024-05-16T14:20:29.637053+00:00
on start callback starts at 2024-05-16T14:20:29.637150+00:00
on start callback ends at 2024-05-16T14:20:32.638305+00:00
on start callback ends at 2024-05-16T14:20:32.638383+00:00
Runnable[3s]: starts at 2024-05-16T14:20:32.638849+00:00
Runnable[5s]: starts at 2024-05-16T14:20:32.638999+00:00
Runnable[3s]: ends at 2024-05-16T14:20:35.640016+00:00
on end callback starts at 2024-05-16T14:20:35.640534+00:00
Runnable[5s]: ends at 2024-05-16T14:20:37.640169+00:00
on end callback starts at 2024-05-16T14:20:37.640574+00:00
on end callback ends at 2024-05-16T14:20:37.640654+00:00
on end callback ends at 2024-05-16T14:20:39.641751+00:00

with_config(config: RunnableConfig | None = None, **kwargs: Any) → Runnable[Input, Output]#

Bind config to a Runnable, returning a new Runnable.

Parameters:

config (RunnableConfig | None) – The config to bind to the Runnable.
kwargs (Any) – Additional keyword arguments to pass to the Runnable.

Returns:

A new Runnable with the config bound.

Return type:

Runnable[Input, Output]

with_fallbacks(fallbacks: Sequence[Runnable[Input, Output]], *, exceptions_to_handle: tuple[type[BaseException], ...] = (<class 'Exception'>,), exception_key: Optional[str] = None) → RunnableWithFallbacksT[Input, Output]#

Add fallbacks to a Runnable, returning a new Runnable.

The new Runnable will try the original Runnable, and then each fallback in order, upon failures.

Parameters:

fallbacks (Sequence[Runnable[Input, Output]]) – A sequence of runnables to try if the original Runnable fails.
exceptions_to_handle (tuple[type[BaseException], ...]) – A tuple of exception types to handle. Defaults to (Exception,).
exception_key (Optional[str]) – If string is specified then handled exceptions will be passed to fallbacks as part of the input under the specified key. If None, exceptions will not be passed to fallbacks. If used, the base Runnable and its fallbacks must accept a dictionary as input. Defaults to None.

Returns:

A new Runnable that will try the original Runnable, and then each fallback in order, upon failures.

Return type:

RunnableWithFallbacksT[Input, Output]

Example

from typing import Iterator

from langchain_core.runnables import RunnableGenerator


def _generate_immediate_error(input: Iterator) -> Iterator[str]:
    raise ValueError()
    yield ""


def _generate(input: Iterator) -> Iterator[str]:
    yield from "foo bar"


runnable = RunnableGenerator(_generate_immediate_error).with_fallbacks(
    [RunnableGenerator(_generate)]
    )
print(''.join(runnable.stream({}))) #foo bar

Parameters:

fallbacks (Sequence[Runnable[Input, Output]]) – A sequence of runnables to try if the original Runnable fails.
exceptions_to_handle (tuple[type[BaseException], ...]) – A tuple of exception types to handle.
exception_key (Optional[str]) – If string is specified then handled exceptions will be passed to fallbacks as part of the input under the specified key. If None, exceptions will not be passed to fallbacks. If used, the base Runnable and its fallbacks must accept a dictionary as input.

Returns:

A new Runnable that will try the original Runnable, and then each fallback in order, upon failures.

Return type:

RunnableWithFallbacksT[Input, Output]

with_listeners(*, on_start: Callable[[Run], None] | Callable[[Run, RunnableConfig], None] | None = None, on_end: Callable[[Run], None] | Callable[[Run, RunnableConfig], None] | None = None, on_error: Callable[[Run], None] | Callable[[Run, RunnableConfig], None] | None = None) → Runnable[Input, Output]#

Bind lifecycle listeners to a Runnable, returning a new Runnable.

on_start: Called before the Runnable starts running, with the Run object. on_end: Called after the Runnable finishes running, with the Run object. on_error: Called if the Runnable throws an error, with the Run object.

The Run object contains information about the run, including its id, type, input, output, error, start_time, end_time, and any tags or metadata added to the run.

Parameters:

on_start (Optional[Union[Callable[[Run], None], Callable[[Run, RunnableConfig], None]]]) – Called before the Runnable starts running. Defaults to None.
on_end (Optional[Union[Callable[[Run], None], Callable[[Run, RunnableConfig], None]]]) – Called after the Runnable finishes running. Defaults to None.
on_error (Optional[Union[Callable[[Run], None], Callable[[Run, RunnableConfig], None]]]) – Called if the Runnable throws an error. Defaults to None.

Returns:

A new Runnable with the listeners bound.

Return type:

Runnable[Input, Output]

Example:

from langchain_core.runnables import RunnableLambda
from langchain_core.tracers.schemas import Run

import time

def test_runnable(time_to_sleep : int):
    time.sleep(time_to_sleep)

def fn_start(run_obj: Run):
    print("start_time:", run_obj.start_time)

def fn_end(run_obj: Run):
    print("end_time:", run_obj.end_time)

chain = RunnableLambda(test_runnable).with_listeners(
    on_start=fn_start,
    on_end=fn_end
)
chain.invoke(2)

with_retry(*, retry_if_exception_type: tuple[type[BaseException], ...] = (<class 'Exception'>,), wait_exponential_jitter: bool = True, stop_after_attempt: int = 3) → Runnable[Input, Output]#

Create a new Runnable that retries the original Runnable on exceptions.

Parameters:

retry_if_exception_type (tuple[type[BaseException], ...]) – A tuple of exception types to retry on. Defaults to (Exception,).
wait_exponential_jitter (bool) – Whether to add jitter to the wait time between retries. Defaults to True.
stop_after_attempt (int) – The maximum number of attempts to make before giving up. Defaults to 3.

Returns:

A new Runnable that retries the original Runnable on exceptions.

Return type:

Runnable[Input, Output]

Example:

from langchain_core.runnables import RunnableLambda

count = 0


def _lambda(x: int) -> None:
    global count
    count = count + 1
    if x == 1:
        raise ValueError("x is 1")
    else:
         pass


runnable = RunnableLambda(_lambda)
try:
    runnable.with_retry(
        stop_after_attempt=2,
        retry_if_exception_type=(ValueError,),
    ).invoke(1)
except ValueError:
    pass

assert (count == 2)

Parameters:

retry_if_exception_type (tuple[type[BaseException], ...]) – A tuple of exception types to retry on
wait_exponential_jitter (bool) – Whether to add jitter to the wait time between retries
stop_after_attempt (int) – The maximum number of attempts to make before giving up

Returns:

A new Runnable that retries the original Runnable on exceptions.

Return type:

Runnable[Input, Output]

Model wrapper that returns outputs formatted to match the given schema.

Parameters:

schema (Dict[str, Any] | Type[_BM] | Type | None) –
The output schema. Can be passed in as:
- an OpenAI function/tool schema,
- a JSON Schema,
- a TypedDict class (support added in 0.1.20),
- or a Pydantic class.
If schema is a Pydantic class then the model output will be a Pydantic instance of that class, and the model-generated fields will be validated by the Pydantic class. Otherwise the model output will be a dict and will not be validated. See langchain_core.utils.function_calling.convert_to_openai_tool() for more on how to properly specify types and descriptions of schema fields when specifying a Pydantic or TypedDict class.
method (Literal['function_calling', 'json_mode', 'json_schema']) –
The method for steering model generation, one of:
- ”function_calling”:
  Uses OpenAI’s tool-calling (formerly called function calling) API: https://platform.openai.com/docs/guides/function-calling
- ”json_schema”:
  Uses OpenAI’s Structured Output API: https://platform.openai.com/docs/guides/structured-outputs Supported for “gpt-4o-mini”, “gpt-4o-2024-08-06”, and later models.
- ”json_mode”:
  Uses OpenAI’s JSON mode. Note that if using JSON mode then you must include instructions for formatting the output into the desired schema into the model call: https://platform.openai.com/docs/guides/structured-outputs/json-mode
Learn more about the differences between the methods and which models support which methods here:
- https://platform.openai.com/docs/guides/structured-outputs/structured-outputs-vs-json-mode
- https://platform.openai.com/docs/guides/structured-outputs/function-calling-vs-response-format
include_raw (bool) – If False then only the parsed structured output is returned. If an error occurs during model output parsing it will be raised. If True then both the raw model response (a BaseMessage) and the parsed model response will be returned. If an error occurs during output parsing it will be caught and returned as well. The final output is always a dict with keys “raw”, “parsed”, and “parsing_error”.
strict (bool | None) –
- True:
  Model output is guaranteed to exactly match the schema. The input schema will also be validated according to https://platform.openai.com/docs/guides/structured-outputs/supported-schemas
- False:
  Input schema will not be validated and model output will not be validated.
- None:
  strict argument will not be passed to the model.
If method is “json_schema” defaults to True. If method is “function_calling” or “json_mode” defaults to None. Can only be non-null if method is “function_calling” or “json_schema”.
kwargs (Any) – Additional keyword args aren’t supported.

Returns:

A Runnable that takes same inputs as a langchain_core.language_models.chat.BaseChatModel.

If include_raw is False and schema is a Pydantic class, Runnable outputs an instance of schema (i.e., a Pydantic object). Otherwise, if include_raw is False then Runnable outputs a dict.

If include_raw is True, then Runnable outputs a dict with keys:

”raw”: BaseMessage
”parsed”: None if there was a parsing error, otherwise the type depends on the schema as described above.
”parsing_error”: Optional[BaseException]

Return type:

Changed in version 0.1.20: Added support for TypedDict class schema.

Changed in version 0.1.21: Support for strict argument added. Support for method = “json_schema” added.

Note

Planned breaking changes in version 0.3.0

method default will be changed to “json_schema” from
“function_calling”.
strict will default to True when method is
“function_calling” as of version 0.3.0.

with_types(*, input_type: type[Input] | None = None, output_type: type[Output] | None = None) → Runnable[Input, Output]#

Bind input and output types to a Runnable, returning a new Runnable.

Parameters:

input_type (type[Input] | None) – The input type to bind to the Runnable. Defaults to None.
output_type (type[Output] | None) – The output type to bind to the Runnable. Defaults to None.

Returns:

A new Runnable with the types bound.

Return type:

Runnable[Input, Output]